I am probably buying an 81 318 fuel injected Chrysler today.

The previous owner wanted to switch to carb years ago and began taking off everything above the intake. That was some time ago, and he never finished. Ive switched a 76 Cordoba from lean burn to carb. It took a new Dizzy, new eddy intake, eddy 625 carb, coil, splug wires, plugs and a box. Plus some vacuum line re-routing/ eliminating. Worked fine.

Since this was a 76 and the 'computer' in the air filter housing only controlled limited items so removing it wasnt a hassle and didnt disrupt any gauges or other systems, and only involved minor wire modifications and only in the engine bay.

Now, I've never owned an 81 chrysler, and it has pieces missing from the intake and up. So, what do I need to convert it? Were 81's still Lean Burn technology, or did they have a more modern ECM that controlled more than just ignition system? If so, is there a ecm somewhere under the hood or in cabin? Did it use sensors on the engine, exhaust and tranny to get info? Will disabling it mess with any other systems besides ignition, and will it affect any accessories or interior gauges/switches?

Basically, if it is different and controls more than the 76 lean burn computer, what all do I need to convert to carb?

Also, if it is better than a 76 lean burn computer, would it be more cost effective, less of a hassle, or just more efficient to just restore the original FI system?

Knowing model and engine size will be a huge help here.

May have just been a lean burn setup that the owner mistakes for fi.

If it was fi, likely a stand alone system, so very similar to changing out a lean burn setup. You'll need to figure out a fuel pump or regulator in addition.

Assuming it was an Imperial, there has got to be somebody on this site that has done the swap. Wait for them to interject. I think the changeover to carb was not real involved IIRC.

There is exactly ONE OEM fuel injected 318 in 1981.

Since you obviously do not know that do not offer up your uninformed opinion.

The 81 EFI system is fairly primitive, your change over will be very similar to the lean b urn conversion you did on the 76.

I'm thinking you would convert it like you would the earlier one; early t cover/mech pump/hughes cam extension/intake/carb/dist.

Yes I said 81 Chrysler on my post, but I forgot to say imperial. And it was definitely fi

Thanks all. I can rewire everything if it's similar to lean burn. Was the computer located in the top hat? Or was it a box somewhere in the cabin, or engine bay?

I just bought the Imperial it is in fantastic condition. I found all of the original fuel injection parts and the Lean burn computer and top hat combo. The guy who owned it passed away and his son said before he began the conversion the fuel injection worked great and the car ran really well. Well I get there and open the hood it looks like all he did was unplug the lean burn computer and took the top hat off and nothing more. I turned the engine over by hand and it rotated nice and smooth. So I'm going to just try and hook the computer and wires back up put some new gas oil spark plugs and coil on and see if it fires up. I'll begin a new thread when I start doing the work because I've never seen this type of setup before and could probably use some advice and pointers. Hopefully I just walked away with a valuable car for cheap. Even the floor pans were in great condition and the carpet too. I also got to keep extra parts that were in the garage including a distributor for a 1969 440 charger and an electronic dizzy as well as in the box nos switches for various things like windows! I also got a full service shop manual for the Imperial

The guy has also got a Shop full of tools and equipment that the grandma is selling off cheap

its your lucky day bro (makes up for the bad ones). I would suggest keeping it in this same thread.

This is the extent of what he removed

Thanks Robert! Even if the motor turns out to be a dud, I'm sure I could rebuild it and still be at less of a cost than the car is worth

The swap is actually more involved than the typical lean burn. the old lean burn is just spark control. In the 81-83 imperials, there is a spark control compute, as well as a fuel control computer. The system is a 'constant flow' vs a typical efi where injectors are just turned on or off. There is the low pressure fuel pump in the tank, plus a high pressure pump on top of the throttle body (the big cylinder in the photo), that constantly puts fuel through the tb but varies its speed based on input from several sensors found on modern cars like 02, speed density, fuel flow meter and fuel temp sensor, among others.

This is an amateur explanation at best, but simply it is much more complex and was so troublesome it was ended after a 3 year run. The factory warranty carb conversions included replacement of the fuel tank, harness modifications and lots more.

What really adds to the trouble here is the digital display gauge cluster and all the fancy options it supported like a mpg readout. So just switching the dizzy, intake, ignition control box, and carb is not good enough if one wants to keep anything but the speedometer working on the dash cluster.

Its definitely doable, I just need to do a lot more research and read everything from the imperilclub.com., a great source of info on these early and unique efi systems. On the other hand, my efi system is complete, and there are mods I can do to eliminate some of the problems it had.. then I could have a plush cruiser. but really I think I'd prob be more happy selling these rare parts to someone else and switch over to carb, and a new cam, some headers and a non lockup converter

the 81 imperials are a cool car.
if i had the $$$ and a really good place to work on them i would put a 3rd gen hemi in one.

before spending much money research what they are worth. new they were 20K+. now not so much.

If you have all the parts, I would try and salvage that EFI system. To me that kind of stuff is cool! Failing that, a carb and a ready to run all-in-one type distributor is super easy to hook up. I'd do an electric fuel pump to make it easy.

Check out the Imperial Owners Club . . .they have lots of information on the fuel injection system and changes to carbs . . .

http://www.imperialclub.com/

Cheers

mark

That looks like the system we called the hydraulic injection system. It was not used on many cars as when I went to the Dodge dealer in 1986 I got some training on it and to be honest I never saw one come in the dealer shop so I never actually worked on one. It was only on certain Chrysler cars and I think only around a year or two. But they said they were not a great EFI system and not many techs out there know much about that system. I actually still have my Mopar training book on that system. My best advise is get rid of it unless you know how to work on it or know a tech who knows alot about it to help you if you have problems. And I would guess parts are hard to find for it if you would ever need any replacement parts. Ron

You won't get it started without the air cleaner on and tight. The ASD just won't let it pump fuel without it all on and tight. The changeover is fairly simple, but more involved than a simple lean burn removal.

I have 2 Imperials an '83 with a Magnum 360/727 and an '82 with the stock efi. The '82 gets insane mileage, rarely under 17 combined and up to 26 straight highway. A lot of that is because of the 2.24 rear. It isn't a complete dog because of the low gearset trans. I had a ton of trouble with vapor lock in the past and haven't had it out since I moved overseas in 2006.

I would try to get it running with the efi. It will hunt rpm a bit, but otherwise they are very smooth and excellent when running right. They are pretty finicky though. The imperial club A12 Mark referenced has a ton of good info including the retrofit manual. You can do it with junkyard parts, but will lose some of the features of the trip computer.

http://www.imperialclub.com/Repair/Year/1981-1983/index.htm

I mentioned the imperial club in my post. I have all their info and tricks, like isolating the asdm from the fender and running it's own seperate ground wire.

Daytona turbo the car already has an electric fuel pump, 2 actually but one gets eliminated in the swap.

383 man yes it's a hydraulic injection system, and also known as a constant flow system.

If I can get it to run right I'll keep it. If not,.the mechanical swap is the easy part, keeping all of my fancy inststrument cluster working properly is the hard part

I *think* most of the stuff will work correctly. The speedo and the odometer do on mine anyway. The guy that did the initial 360 swap on mine put a Mirada tank and sender. I think the gas gauge can be a minor problem if you stick with the original stuff. The trip computer probably won't work too great, but even my stock efi car gets a little squirrely with the fuel gauge and telling me I am getting 99 mpg. You can tell if you review the conversion kit what you need to try to keep it all working right, but you probably won't care about some of it.

My cars are kind of a strange case because the backyard converted car was done up right, while my stock efi car was just kept running for years and got kind of cobbled. I really just bought it for the seats, but it got such good mpg and had cold a/c, so I ended up daily driving it for 3 or 4 years.